Hydraulic jack means



March 28, 1967 F. s. PEARNE 3,310,947i

HYDRAULIC JACK MEANS Filed July 15, 1964 3 Sheets-Sheet 1 INVENTOR.

FRANK, s. PEA E B1; I

Arrow EYS March 28, 1967 v F. s. PEARNE 3,310,941

HYDRAULIC JACK MEANS Filed July 15, 1964 v 3 Sheets-sheaf, a

INVENTOR FR NK PEARNEJ,

ACI'TORNEYS March 28, 1967 F. s. PEARNE 3,319,945

HYDRAULIC JACK MEANS Filed July 15, 1964 5 Sheets-Sheet 3 INVENTOR. v FRANK S. PEARNE Y (all) v f i fl (ff 3, ,4. l v,

Awoiwavs United Staes atent O 3,310,941 HYDRAULIC JACK MEANS Frank S. Pearne, San Gabriel, Calif, assignor to Pearne and Lacey Machine Company, Inc, Los Angeles, Calif., a corporation of California Filed July 15, 1954, Ser. No. 332,736 2 Claims. (CI. 63-52) This invention relates to hydraulic pump means and, more particularly, to an improved pump means for selectively supplying hydraulic fluid to one or more hydraulic jacks.

The invention is particularly concerned with a hydraulic pump for supplying fluid to jacks which are mounted at the corners of a camper coach so that the coach may be raised and lowered for placement on or removal from the bed of a pick-up truck. In order to lift such a load safely, it is desirable to supply hydraulic fluid to individual jacks or to jack pairs that are mounted on the sides or the ends of the load, and to raise the individual jacks or jack pairs in increments so that the load will be balanced. It is also necessary to prevent a jack from being overloaded if the load is improperly lifted or lowered. In order to satisfy these requirements, a hy draulic pump and selector valve has been devised that permits the pumping of hydraulic fluid to individual jacks or to jack pairs that are located at the sides or at the ends of the load but prevents the pumping of hydraulic fluid to jack pairs that are located at diagonally opposite corners of the load. The invention also contemplates the provision of a valve that will prevent further pumping of hydraulic fluid to a jack when the fluid pressure in that jack reaches a predetermined maximum value.

An object of the present invention is to provide a hydraulic pump for supplying hydraulic fluid to a plurality of jacks, and to provide a selector valve for the pump so that the fluid may be supplied to individual or groups of jacks.

It is a further object of this invention to provide a selectively operated fluid-release mechanism that may be actuated by the pump handle.

It is a still further object of this invention to provide a pump for supplying hydraulic fluid to a plurality of jacks and having an overload valve to prevent the loading of a jack beyond a predetermined maximum value.

Other objects and advantages of the invention will become more readily apparent when the same is considered in connection with the following detailed description and the accompanying drawings, wherein:

FIG. 1 is a schematic, perspective view of a camper coach provided with a hydraulic pump and jacks according to the present invention;

FIG. 2 is a schematic illustration of the hydraulic circuit according to this invention;

FIG. 3 is an elevational view of the hydraulic pump according to this invention;

FIG. 4 is a cross-sectional view of the hydraulic pump, the plane of the section being indicated by the line 44 in FIG. 3;

FIG. 5 is a cross-sectional view of the pump, the plane of the section being indicated by the line 55 in FIG. 4;

FIG. 6 is a fragmentary, cross-sectional view of a portion of the pump, the plane of the section being indicated by the line 66 in FIG. 5;

FIG. 7 is a cross-sectional view of the pump, the plane of the section being indicated by the line 77 in FIG. 4; and

FIG. 8 is a cross-sectional view of the pump, the plane of the section being indicated by the line 8-8 in FIG. 4.

Referring now to the drawings, a hydraulic pump 10 is illustrated. As may be seen in FIG. 1, the pump 10 draws hydraulic fluid from a reservoir 11 and, as will hereinafter become apparent, selectively supplies the fluid to a right front jack 12, a left front jack 13, a right rear jack 14, and a left rear jack 15. The jacks 12-15 are fixed to the body of a camper coach 16. When the jacks are extended and the camper coach is in an elevated position, as is shown in FIG. 1, a pick-up truck may be backed under the coach between the front jacks. When the truck is in position, the coach may be lowered onto the truck bed. The coach may be removed from the bed by raising the jacks, removing the truck, and lowering the jacks so that the rear end of the coach rests on the ground and the front of the coach is supported by the front jacks 12 and 13.

The pump 10 comprises a pump block 17, a spacer ring 18, and a selector valve block 19, which are all bolted together by machine screws 20. The pump block 17 is provided with a cylinder bore 21 and a piston 22 is slidably mounted in the bore 21. The top of the piston is provided with a clevis 23, and a link 24 is pivoted to the piston within this clevis. The link 24 is pivoted to a pair of links 25, which are, in turn, pivoted to a plate 26 fixed to the pump block 17. A hollow operating handle 27 is slipped over a projecting end 28 of the link 24. The handle 27 is provided with a washer 29 which butts against the upper end of the pump block 17 at the completion of a downstroke.

When the operating handle 27 is raised, hydraulic fluid is drawn from the reservoir 11 into the cylinder 21 through a hose 36 (FIGS. 4 and 6), an inlet port 31, an inlet passage 32, and past a one-way ball-check valve 33 (FIG. 6). When the piston is forced downwardly in its cylinder, the ball-check valve 33 is seated, and the hydraulic fluid is forced into a fluid outlet passage 34 (FIG. 4). The pressure of the fluid in the passage 34 opens a one-way ball-check valve 35 against the bias of a relatively weak spring 36. The hydraulic fluid then flows to a cylindrical chamber 37 which is provided in in the spacer ring 18.

A nylon selector spool 38 is provided in the chamber 3'7 and has a diameter that is slightly less than the diameter of the chamber 37 and a height that is slightly less than the longitudinal extent of the chamber 37. The selector spool 38 is pinned to a selector spool handle 39 which extends axially through the spool 38 and through the selector valve block 19.

The handle 39 has an end portion 40 which is bent to extend degrees to the axis of the selector spool 38. Spring washers 41 are provided between the bottom of the block 17 and the top of the selector spool to press the selector spool 38 downwardly to form a fluid seal between the spool 38 and the top of the block 19.

As may be seen most clearly in FIG. 7, the bottom face of the spool 38 is provided with a groove or slot 42. The slot 42 has a longitudinal axis A that is offset from the diameter of the spool 38 and defines an angle of 45 degrees with respect to the axis B of the end portion 40 of the handle 39.

As may be seen most clearly in FIGS. 2 and 8, ports 43, 44, 45, and 46 are drilled into the upper surface of the block 19. The ports 43-46 are located at the corners of an imaginary square S having its center at the axis C of the handle 39. The distance between the axis C of the handle 39 and a side of the imaginary square S corresponds to the distance between the axis C of the handle 39 and the longitudinal axis A of the slot 42. The ports 43-46 are located within an imaginary circle which has a radius corresponding to the distance between the axis of the handle 39 and an outside edge 47 of the slot 42. It is apparent, therefore, that the slot 42 is always in fluid communication with at least one of the ports 43 .6, and when the longitudinal axis of the slot 42 is in substantial alignment with one of the sides of the imaginary square, the slot .42 is influid communication with two of the ports 43-46. In the illustrated position, the slot 42 provides fluid communication between the chamber 37 and the ports 43 and 44.

As may be seen in FIG. 8, the ports 43-46 are in fluid communication with ports 48, 49, 50, and 51, respectively. As is illustrated schematically in FIG. 2, the ports 48-51 are respectively connected to the jacks 15, 13, 12, and 14.

The illustrated position ofthe selector spool 33, therefore, provides a flowpath from; the cylinder 21 to the jacks located on the right side of the load (jacks 13 and 15). The pump is fixed to the load and the selector spool 38 is fixed to the handle 39 so that the end portion 40 of the handle points toward a portion of the pump block that corresponds to the location, relative to the load, of the jack or jack pairs that are to be operated. As may be seen in FIG. 2, the jacks 13 and are being operated and the end portion 40 is pointed toward the left-hand side of the pump block. If the end portion 40 of the handle and, therefore, the selector spool 38 are rotated 45 degrees in a clockwise direction, the end portion 40 will point toward a portion of the pump block that corresponds to the location of the jack 13 relative to the load (toward the left front corner of the pump block) and the cylinder 21 will be placed in fluid communication with the ports 44 and 49 to operate the jack 13, as may be seen in phantom outline in FIG. 2. It may be seen that as the end portion 40 is turned clockwise in 45-degree increments, the jacks 13 and 12, the jack 12, the jacks 12 and 14, the jack 14, the jacks 14 and 15, and the jack 15 will be selectively operated in the order stated. 1

When hydraulic fluid is pumped to a pair of jacks, these selected jacks are manifolded together since the slot 42 opens the ports leading to the selected jacks to the fluid being pumped and the fluid is free to flow between the selected jacks. The action simulates a safe and reliable three-point lifting arrangement since the two jack cylinders that are shut off are, in effect, locked while the other two are manifolded.

The location of the slot 42 insures that diagonally opposed jacks will not be operated together. If diagonally opposed jacks were operated, a large percentage of the remaining load would be placed on only one of the remaining jacks.

To insure that a jack or pair of jacks is not loaded beyond a predetermined pressure, an overload valve is provided in the block 17. The overload valve comprises a bore 52 which extends from the bottom of the cylinder 21 into the block 17 and a threaded axial counterbore 53. A hollow nylon sleeve 54 is threaded into the counterbore 53 and is normally closed at its bottom end by a ball-check valve 55. The valve 55 prevents fluid flow from the bore 52 to the cylinder 21, but permits fluid flow from the cylinder 21 to the bore 52 against the bias of -a relatively strong spring 56. The spring 56 is selected so that the valve 55 will be unseated only when a predetermined maximum pressure is exceeded in the cylinder 21. This pressure is transmitted from the jack or jacks being loaded, and, when that pressure is transmitted to the cylinder 21, the valve 35 will be seated by its spring 36. Any additional fluid drawn from the reservoir 11, past the valve 33 and into the cylinder 21, will be forced past the valve 55, into the bore 52, and will be returned to the reservoir through a passage 57, the port 31, and the hose 30.

Fluid may be exhausted from a jack or pair of jacks by pulling the operating handle outwardly so that the washer 29 will clear the upper end of the pump block 17, and by pushing the operating handel 27 downwardly until the piston 22 bottoms in the cylinder 21. The bottom face of the piston 22 pushes a pair of rods 58 and 59 downwardly to open the valves 35 and 55 respectively. When these valves are opened, fluid is permitted to flow from the chamber 37 past the valves 35 into the cylinder 21 through the hollow sleeve 54, past the valve 55 and into the reservoir 11. The position of the previously described 4 selector spool 38 determines which jack or jack pairs may be retracted in this manner.

Obviously many modifications and variations of the specific form of the invention shown and described herein are possible in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically shown and described.

What is claimed is:

1. A fluid pressure jack assembly for selectively supplying fluid to the cylinders of one or a plurality of jacks, comprising a pump cylinder, a piston reciprocally mounted in said cylinder, a block defining a fluid distributing chamber, fluid passage means connecting said pump cylinder and said fluid distributing chamber, a flow control valve in said passage means permitting fluid fiow from said pump cylinder to said fluid distributing cham her, a plurality of fluid ports in said block communicating with said fluid distributing chamber, conduit means connecting each of said ports respectively to a corresponding one of the plurality of jack cylinders, a selector means in said chamber to selectively open and close said ports so that any one port or a predetermined plurality of ports may be opened While the remaining ports are closed,

operating means including position indicating means for moving said selector means to selectively open and close said ports, said block and indicating means having design configurations such that their relative positions are determinable by the sense of touch, and said block being oriented relative to the location of the several jack cylinders so that the position of the indicating means relative to said block indicates the jack or plurality of jacks being supplied with fluid pressure.

2. A fluid pressure jack assembly for selectively supplying fluid to the cylinders of four jacks which are located at the corners of a load, comprising a pump cylinder, a piston reciprocally mounted in said pump cylinder, a block defining a fluid distributing chamber, fluid passage means connecting said pump cylinder and said fluid distributing chamber, a flow control valve in said passage means permitting fluid flow from said pump cylinder to said fluid distributing chamber, four ports located at the corners of an imaginary square at the bottom of said fluid distributing chamber, each corner of said square being defined by a port which is connected to a corresponding one of said jacks, a selector spool in said fluid distributing chamber having a flat face engaging the bottom of said chamber, a groove in said fiat face, said groove having a length at least sufl'icient to bridge between a pair of ports at adjacent corners of said imaginary square, operating means fixed to said selector spool for pivoting said spool about an axis which is perpendicular to the bottom surface of said fluid distributing chamber and which passes through the center of said imaginary square, said. groove being offset from said :axis and having an outside edge spaced from said axis a distance that substantially corresponds to the distance between said axis and a port, said operating means including position indicating means, said block and indicating means having design configurations such that their relative positions are determinable by the sense of touch, and said block being oriented relative to the position of the several jack cylinders so that the position of the indicating means relative to said block indicates the jack or plurality of jacks being supplied with fluid pressure.

References Cited by the Examiner UNITED STATES PATENTS 569,574 10/1896 Caldwell 6052 1,002,372 2/1911 Dalzell l37625.ll X 1,524,159 1/1925 Sunderrnan 6052 1,856,226 5/1932 Rustin et a1 137----62$.l1 2,251,293 8/1941 Schwartz et al. 6052 X 2,577,539 12/1951 Page 6052 JULIUS E. WEST, Primary Examiner. 

1. A FLUID PRESSURE JACK ASSEMBLY FOR SELECTIVELY SUPPLYING FLUID TO THE CYLINDERS OF ONE OR A PLURALITY OF JACKS, COMPRISING A PUMP CYLINDER, A PISTON RECIPROCALLY MOUNTED IN SAID CYLINDER, A BLOCK DEFINING A FLUID DISTRIBUTING CHAMBER, FLUID PASSAGE MEANS CONNECTING SAID PUMP CYLINDER AND SAID FLUID DISTRIBUTING CHAMBER, A FLOW CONTROL VALVE IN SAID PASSAGE MEANS PERMITTING FLUID FLOW FROM SAID PUMP CYLINDER TO SAID FLUID DISTRIBUTING CHAMBER, A PLURALITY OF FLUID PORTS IN SAID BLOCK COMMUNICATING WITH SAID FLUID DISTRIBUTING CHAMBER, CONDUIT MEANS CONNECTING EACH OF SAID PORTS RESPECTIVELY TO A CORRESPONDING ONE OF THE PLURALITY OF JACK CYLINDERS, A SELECTOR MEANS IN SAID CHAMBER TO SELECTIVELY OPEN AND CLOSE SAID PORTS SO 